Integrated circuit packages enclose and protect integrated circuits while allowing for communication between the integrated circuits and external devices. For example, most conventional packages include a substrate on which an integrated circuit is mounted. Vias are used to connect points (e.g., bumps or pins) on an external or interior surface of the substrate to points on an internal surface of the substrate. Forming vias typically includes drilling holes (e.g., by laser) and then introducing a conductive material into the holes (e.g., by plating the holes or by inserting conductive rivets into the holes). Conventional packages typically include traces connecting the vias to wire bond pads on an internal surface of the substrate. Bond wires connect the bond pads on the internal surface of the substrate to bond pads on a surface of the mounted integrated circuit.
In contrast to conventional devices, U.S. Pat. No. 7,042,098 discloses a package including “vias have[ing] a via capture pad to which a wire may be wire bonded so that the wires from the [integrated circuit] to the substrate top side directly contact the vias at their capture pads without the need for traces from a top side bond pad to a via” (abstract).
U.S. Patent Application Publication No. 2004/0262039 discloses “a first wire-bond pad and a first via that is disposed directly below the first wire-bond pad in the . . . wire-bonding substrate” (abstract).
U.S. Pat. No. 7,053,489 discloses an arrangement where “a nail head contact is applied directly to a support surface at the site of the through-plating, without further metallization being present on the surface.” Col. 2 lines 4-7. The '489 patent further emphasizes that “only the hole through the support to form the through-plating is metallized” in order to “avoid the need for an expensive substrate surface.” Col. 2 lines 7-8 and 16-17.
These prior art references, however, fail to address technical challenges associated with direct wire bonding to vias.